Hi did anyone ever fit an fcr 37 to their bikes and if so were there any problems? as i have got the possibility to get one cheap
i would welcome any info,
thanks
Simon L

 

Dont think so man.... cant say i have herd of this carb on this bike....

 

There are used on MX bikes like the KX250F. The KX250F makes a lot more HP than the KLX250. It flows a lot of air to produce the HP and needs a carbie big enough to supply more fuel than is needed for the KLX motor. I'd suggest the 37 is too big for the KLX

 

You are talking some pretty high flow. Most 250 MXers use that diameter, but they're flowing a lot more air at higher RPM. Unless you change your cam profile drastically, it's probably not a great idea.

However, if you are getting the carb for a prayer and have the time to play around that might be aninteresting experiment. I think you might lose alot on the low end and I'm not sure the pulse will be right with stock cam profile for it to ever run perfectly.

It's pretty much for arun it at WOT and do lots of valve jobs style of riding[8D]

 

Ihad a Keihin FCR 37 from an '05 Yamaha WR250. I didn't get too far into fitting it because I found out the carb was junk. Yamaha has problems with the float valve leaking (or so Carb Parts Warehouse told me), and there is no fix for it. The float valve seat is not sold as a separate part. If you're buying an OEM carb, make sure you check this out first.

But I do know this much. The air intake side of the carb (theend that fits into the air box boot) is the same size as a 34mm CVK. The spigot side of the carb (theend that fits into the intake manifold) is much larger. The 34mm CVK spigot has a 40mm outside diameter, while the 37mm FCR has a something like a 48 mm diameter (I can't remember exactly). The FCR spigot has about the same O.D. as the rubber intake manifold. The FCR is also 5/8" (@16mm) shorter than a CVK from front to back. What others have done is used a 2" piece of silicon hose and went over both the spigot of the FCR and the rubber intake manifold (instead of inside the intake manifold). An issue that arises is that the accelerator pump hits the exhaust because the FCR is also much wider than the CVK from side to side. You would need to offset the carb by about 3/16". That is as far as I got before scrapping the carb.

 

Sorry i forgot to mentioni'vegot a 300cc barrel fitted (oops) i dont know if that will make a difference to everyones opinions. thanks for everones input so far.
The fitment at the engine intake shouldn't be a problem as we have a specialist company here who can supply odd size rubber flanges, so hopefully i should be able to get a match.
The carb itself is super cheap in fact almost free so i guess it would make a worthwhile experiment, if for no other reason than just to let the forum members knowof the pitfalls.

Heres hoping!
Simon L

 

Is there any other kind ofriding

Heres the link for the carb people we all use here in the UK might be of use as a reference for all you guys
http://www.allensperformance.co.uk/index.html

Simon L

 

Good luck! I'm sure most people here will be interested in the outcome. My guess is it will be a beyotch to get jetted properly, but once you're there you migh have something.

 

there was a fcr37 for sale on ebay that was reported to have been used on a klx250s. It came off of a wr250f. The owner said that it was fitted and running on the bike but had a slight clearance issue with it hitting the muzzy pipe, that was the reason for selling it. He said that the bike ran very well with the stock jetting that was in the carb. Nobrakes has also reported that the fcr35 on his bike is very close to the muzzy pipe but did not touch.

 

I looked at this aftermarket or dealers here suck. If you don't go in with your own parts number and who sells it you're screwed. Also the shipping cost of bring things across fromUSA to Canada,sometimes greatly out way buying stuff. Must cases it become double the cost. so a factory piece would save me a big shipping cost. I would like to try this carb say it's for a 250 to 375 cc engine.